This invention relates to a multi-purpose kitchen apparatus for processing foods, with a container having arranged in a bore in the container bottom a bearing sleeve in which a tool shaft extending through the container bottom is journalled for rotary movement therein, with the one end of the tool shaft being adapted to be connected with a drive motor through a coupling means, while the other end is adapted to receive a processing tool for processing the foodstuffs. Such multi-purpose food processors are employed for blending, mixing, kneading, shredding, chopping, juice extracting, whipping, etc. foods, being frequently usable also as special appliances such as blenders, juice extractors.
A prior art domestic appliance is known from DE-22 58 711 A1. In this prior art structure, for mounting the tool shaft the bearing sleeve receiving the tool shaft is a press fit within the container bottom which is made of a plastic material. In the operation of such a kitchen appliance, a substantial quantity of heat is generated by friction occurring between the tool shaft and the bearing sleeve, which may result in major deformations in the bottom area of the container, thus involving the risk of leakage. To overcome these thermal problems, the known kitchen appliance provides a tool shaft made from a special material of a particularly high thermal conductivity, which has additionally a chromized coating of a particularly low peak-to-valley roughness. It will be obvious that this necessitates very high material and manufacturing expenditure.
It is a further disadvantage of the known kitchen appliance that all vibrations of the tool shaft are directly transmitted into the container through the bearing sleeve, resulting in considerable noise, all the more so since the container acts as an excellent resonant cavity for the shaft vibration transmitted by structure-borne noise. Also, the two-part construction of container and bottom portion with the bearing arrangement results in a highly complex structure involving high cost.